it seems like you already know how to measure gauge, since you know you have to go down a few sizes to get gauge. That's 95% of the battle right there. As far as keeping stitches uniform, besides practicing there isn't much you can do. You might try changing needle material, like try metal, plastic and bamboo and see which one is easiest for you. Dishcloths are a good way to practice gauge/uniformity, beause they're small and functional.